Research Interests:

Surface and interfacial properties of polymers, phase transitions in polymers, directed self-assembly processes, the use of polymers as scaffolds and templates for the generation of nanoscopic structures, the interfacial assembly of nanoparticles, hierarchical ordering of synthetic and biologically-based systems, wrinkling and crumpling of thin polymer films, polymers in ionic liquids, and the structure and morphology of polymer-based photovoltaic materials.

Current Research:

Polymers and block copolymers offer unique avenues for the fabrication of nanostructured materials. Over the past decade we have been developing routes and understanding the mechanism by which the orientation of the morphology in thin block copolymer films can be controlled with exquisite precision. This has given rise to a plethora of applications of polymers in current technologies. Efforts in our group have recently focused on: developing large scale arrays of nanoscopic elements using block copolymers having exceptional long-range order and, by chemical modification of the polymer; minimizing the size scale of the elements; simplifying the fabrication process; and, by use of supercritical fluid (SCF) CO2, performing spatially-specific metallization chemistries within the microphase separate morphologies. We are currently exploring electronic, magnetic, biological and sensory applications of the scaffolds and templates that are generated. In addition, by understanding the interfacial activity of nanoparticles we are developing routes to achieve multi-length scale ordering of nanoparticles that are emerging as interesting platforms for encapsulation and diffusion barriers. By use of electrostatic pressures at polymer interfaces we are also studying the enhancement of interfacial fluctuations and routes by which the lateral length scale and amplitudes of the fluctuations can be controlled. Finally, both hydrostatic pressure and SCF CO2 are being used to control the phase behavior in entropically driven phase transitions in polymer mixtures and block copolymers, discovered in our group, and on are recently discovered closed-loop phase diagram. Optical, laser scanning confocal, electron and scanning force microscopies, and neutron (reactors and spallation sources), light and x-ray scattering (in-house and synchrotron-based) are key techniques used in these studies.